1. Field of the Invention
The present invention relates to a satellite information update system. More specifically, the present invention relates to a satellite information update system, a positioning auxiliary information provision device, a positioning auxiliary information provision device control method, a positioning auxiliary information provision device control program, and a computer readable recording medium having recorded therein the positioning auxiliary information provision device control program, which are related to positioning processing based on a signal form a position information satellite.
2. Background Information
A positioning system for determining the current position of a SPS receiver by utilizing a satellite navigation system using a position information satellite, for example, a SPS (Satellite Positioning System), has conventionally been put to practical use. Among SPS receivers used in such a positioning system, there are some that have a mechanism to receive satellite information, including satellite orbit information, etc., by radio communication from an external device, thus seeking to shorten positioning time and improve positioning precision. Such SPS receivers having satellite information stored in a storage device are configured to use the satellite information stored in the storage device when performing positioning operations. When this storage device is a high-speed storage device, for example, a cache memory inside a hard disk, the satellite information can be browsed at high speed.
On the contrary, although satellite information from a specific SPS satellite has stopped being delivered due to a malfunction of the SPS satellite or the like, the aforesaid SPS receiver has the satellite information of the SPS satellite stored in the cache memory, in which case positioning processing is started based on the invalid satellite information. Consequently, the aforesaid SPS receiver cannot acquire an accurate positioning result, which therefore results in the wasteful consumption of processing time, processing power, and electric power.
An SPS position detection system, which utilizes a control channel to receive periodically SPS positioning assistant information transmitted periodically from a radio base station, has been proposed to deal with this problem such a system is disclosed in JP-A-2002-221565 which is hereby incorporated by reference. However, in the aforesaid SPS position detection system, information other than information indicating that the satellite information is to be updated is also periodically transmitted and received, which therefore provides a heavy burden with regards to information processing on the satellite information transmission and reception sides.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved a satellite information update system, a positioning auxiliary information provision device, a positioning auxiliary information provision device control method, a positioning auxiliary information provision device control program, and a computer readable recording medium. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.